I. Field of the Invention
This invention relates to a roller bearing which comprises at least one sealing ring disposed with respect to an outer ring, and wherein the sealing ring is capable of forcing circulation of lubricant or lubricating oil.
II. Description of the Prior Art
Generally, a sealing ring which is used as a sealing means for roller bearings which have an outer ring having at least a radially and inwardly directed flange, such as needle roller bearings, long cylindrical roller bearings and cylindrical roller bearings, is fixedly attached to the outer ring and constitutes a contiguous or noncontiguous sealing portion.
Accordingly, there are encountered problems such as the requirement for special work and/or troublesome handling in assembling the sealing member to the outer ring.
In view of these drawbacks, the present inventor has previously developed a sealing structure attached with a sealing ring or rings which enables elimination of special work, as well as facilitating assembly of the sealing ring, and has filed a Japanese utility model application.
The prior invention contemplates forming a recessed groove or grooves on a radially outer circumference of the sealing ring to constitute a region of labyrinth sealing between at least a part or the entire flange of the outer ring and the sealing ring. The inner circumference of the sealing ring is fixedly attached to the shaft, and the sealing ring is integrally assembled to the flange of the outer ring. This sealing structure is believed to be the most similar invention filed prior to the present invention.
As noted, this prior development comtemplates a labyrinth sealing region between the flange of the outer ring and the sealing ring to thereby prevent invasion of foreign matter or particles from outside of the bearing. However, such a bearing is not wholly satisfactory for avoiding the problems caused by the foreign matters, such as iron dust particles entrapped in lubricating oil, when this type of bearing is received in a case containing lubricating oil and lubrication of the bearing is performed by the lubricating oil surrounding the bearing. The present invention has been accomplished to eliminate the drawbacks encountered in the sealing structure of the inventor's prior invention.